1. Field of the Invention
The present invention relates to a working apparatus for handling a sheet by a robot arm or finger.
2. Description of the Prior Art
In prior art working apparatus such as an industrial robot or welding robot, positioning mechanisms have had little freedom and the entire apparatus is fixed in many cases. Accordingly, it is hard to provide a feed device of a copying machine or an automatic paging device for a passbook, unless sheets of a predetermined material are handled at a predetermined position and in a specific application. Even in such devices, sheets are double fed, folded, broken or jammed and perfect sheet feeding is not attained.
When sheets are to be handled without limitation to the mount location of the sheets and the material of the sheets, further problems are encountered. For example, when books or documents of various types are to be turned page by page, it is almost impossible to turn pages of the book or documents unless the size of the sheets is fixed because of various sizes and materials of the sheets.
One prior art technique for a sheet handling device is shown in Japanese Laid-Open Patent Application 58-139939, in which a double-feed of the sheets is prevented by an air suction mechanism. Several sheets are sucked by the air suction mechanism and the extra sucked sheets except one are returned by an air jet from an original document sucking device and a rotating member and a back side of the one sucked sheet is sucked by the original document sucking device and the suction of the sheet is checked by monitoring a load current to a suction blower. If only one sheet has been separated, the original document sucking device presses the remaining sheets and the separated sheet is fed to a feed unit.
In the above patent application, the sheet double-feed prevention device prevents a double-feed of sheets in a stationary apparatus such as a copying machine, electronic file facsimile or printer which does not require positioning. It needs a duct, a vacuum chamber and a suction blower and hence the apparatus is large and cannot operate at a high speed. It also cannot turn a page of a book.